1. Field
The present invention relates to a wireless communication system, and particularly, to a method and a device for flexibly transmitting a reference signal based on a state of using resources so as to reduce waste of resources occurring due to aperiodic transmission of a channel estimation reference signal for scheduling resources in an OFDMA wireless communication system.
2. Discussion of the Background
As communication systems have developed, various wireless terminals have been utilized by consumers, such as companies and individuals.
A current mobile communication system, for example, 3GPP, Long Term Evolution (LTE), LTE-Advanced (LTE-A), and the like, may be a high capacity communication system capable of transmitting and receiving various data such as image data, wireless data, and the like, beyond providing a sound-based service. Accordingly, there is a desire for a technology that transmits high capacity data, which is comparable with a wired communication network. Also, the system is required to include an appropriate error detection scheme that minimizes loss of information and increases transmission efficiency of the system so as to enhance performance of the system.
Also, varied reference signals have been utilized in current various communication systems to provide information associated with a communication environment and the like, to a counterpart apparatus through an uplink or a downlink.
For example, an LTE system, which is one of the mobile communication methods, transmits, to a base station, a channel estimation reference signal (hereinafter referred to ‘sounding reference signal’ or ‘SRS’) indicating a channel state of a user equipment (UE) during uplink transmission, and transmits a reference signal or a cell-specific reference signal (CRS) at every subframe to recognize channel information during downlink transmission.
In general, the reference signals for channel estimation and the like may be periodically generated by a reference signal transmitting apparatus, that is, a UE in the case where the reference signal corresponds to an uplink reference signal, and a BS in the case where the reference signal corresponds to a downlink reference signal, and may be transmitted to a reference signal receiving apparatus.
Although aperiodic transmission of a channel estimation reference signal and the like has been discussed in consideration of a flexibility of a communication system and the like, a detailed scheme thereof has not yet been determined.